Sequencing of DNA (Deoxyribonucleic Acid) is the determination of the precise sequence of nucleotides in a sample of DNA. The most common method for DNA sequencing was developed by Frederick Sanger and is referred to as the Dideoxy method or Sanger sequencing. The dideoxy method makes possible DNA sequencing based on sequencing of DNA fragments. Today, automated sequencers are used to generate computer-readable sequence data from DNA fragments. In its raw form, the sequence data includes electropherograms. An electropherogram includes an electropherographic signal for each of the four types of nucleotides (A Adenine, C Cytosine, G Guanine, and T Thymine). From amplitude peaks in the electropherographic signals, codes (A, C, G, T) can be derived for the types of nucleotides. In addition to the electropherographic signals, the sequence data from a sequencer may also include the encoded sequence of the DNA fragment, i.e. a sequence of codes of the derived nucleotide types. Typically, the sequences are validated through human intervention by an experienced lab technician, for example. For validation, the sequence of a DNA fragment is compared to a suitable reference sequence. For that purpose, the human operator must first search and retrieve “manually” a reference sequence from a database. Subsequently, the human operator compares visually the sequence of a DNA fragment to the reference sequence by checking nucleotide by nucleotide the correspondence of the respective nucleotide codes. Manual search, selection, and retrieval of reference sequences are time consuming and provide no guarantees that a reference sequence is selected optimally. There may very well exist a more suitable reference sequence providing a better match to the multiple sequences of DNA fragments to be validated and, therefore, helping to save time and reduce errors. Moreover, the search and selection of a reference sequence by a human operator is error prone as human and manual interventions take place.